Marine Helo units are designated H (Helo/Rotary)
HML-767 Marine Light Helicopter Squadron 767
HMM-261 Marine Medium Helicopter Squadron HMLA-775 Marine Light Attack Helicopter squadron
HMH-769 Marine Heavy Helicopter Squadron

Support Squadrons/headquarters Sqs/Maintenance Squadrons/etc;
H&MS-11 Headquarters and Maintenance Squadron
MABS- 11 Marine Airbase Squadron
MALS- Marine Aviation Logistics Squadron
MACS- Marine Air Control Squadron
MTACS- Marine Tactical Air Command Squadron
The highest level of aviation command is the Marine Aircraft Wing- composed of two or more Aircraft Groups (and support units)
There are 4 Marine Air Wings- 3 regular and 1 reserve.
There are several types of Groups - Fixed wing fighter/attack Groups MAG-11/12/13/14, etc.
Helicopter Groups- MAGs16/16/39etc.
Marine Air Control Groups MACG-18/28/38
Marine Wing Support Groups - MSWG-17/27/37, etc.
Marine Wing Headquarters Squadron MWHS-1/2/3/4 (1 for each wing)
For example- The 2nd Marine Air Wing has several Groups- MAGS-14, 32, 26 (Helo)
Each Group has several squadrons- VMF/A, HMM, VMGR, etc.
Naturally, the support tail goes with all of them.

All of Marine Aviation units are task organized. For example, the Marine Expeditionary Unit could contain elements of a Harrier (VMA) squadron, medium helicopters (HMM-CH-46's), Heavy Lift Helos (HMH- CH-53's), plus the admin and maint support they would need while deployed with the Amphibs aboard an LHA/LPD, etc.
We also detach a squadron to flesh out a Carrier Air Group- aboard the Stennis/Roosevelt, etc. VMFA-312 for example with CVW-11.